That is probably because you are checking for Visible()==true when you should be checking for Exists()==true.

More than likely the element is not there. Check it with spy and make sure that it is actually existing before you check for visible, because if it isn't there Ranorex won't be able to check if it is visible or not.

N.B. Ranorex will search for the item until the timeout specified in the repository is reached. So if you want for Ranorex to be faster you can reduce the search timeout according to how long it usually takes to find the item.